1. Field of the Invention
The present invention is generally in the field of semiconductor manufacturing. More specifically, the invention is in the field of semiconductor die packaging.
2. Background Art
Leadframe based molded packages are commonly used in semiconductor packaging. As a part of efforts to reduce the inductance values on the ground connection of the semiconductor die, an “exposed paddle” leadframe based molded package has been developed. In an exposed paddle leadframe based molded package, the bottom surface of the paddle is not encapsulated in mold compound. The metal on the bottom surface of the paddle is left exposed in order to electrically connect the bottom surface of the paddle to a printed circuit board (“PCB”) ground during a re-flow solder process.
Unfortunately, this conventional approach is not suitable for some applications when it comes to heat dissipation. For example, in some laser driver optical head applications heat cannot flow from the semiconductor die, down through the paddle, and into the PCB, because an optical laser is in the thermal path. Conventional approaches have existed wherein the electrical connections and primary thermal path (i.e. heat dissipation path out of the semiconductor die) are both on the same side of the package, i.e. heat is spread from the semiconductor die down into the PCB where the electrical connections are made.
Thus, it would be desirable to dissipate heat from one side of an IC package and provide electrical connections from the opposite side of the IC package in certain applications. One could envision providing thermal vias within the IC package, leading from the semiconductor die to the surface of the IC package on the opposite side of the IC package as the electrical connections. However, formation of such thermal vias within the mold body would be quite difficult, slow, and expensive.
In addition to the problems with conventional approaches mentioned herein, some previous attempts exhibit outer leads that extend further than necessary from the sides of the IC package. These IC packages have relatively large footprints, which is typically undesirable. Large footprints are especially undesirable for area-challenged consumer communication, gaming, hand-held applications, and the like.
Thus, it is seen that there is need in the art for a leadframe molded package with a relatively small footprint. The leadframe molded package should exhibit improved heat dissipation characteristics from one surface and have electrical connections emanating from an opposite surface of the package. The IC package should also allow for efficient and cost-effective manufacturing.